1. Field
The present embodiments generally relate to methods and processes for providing power for sub-sea uses. More particularly, embodiments of the present invention relate to methods and processes for providing power to sub-sea equipment disposed in the vicinity of the sea-floor.
2. Description of the Related Art
Water injection and gas lift techniques are two of a number of processes used to artificially lift liquid, typically hydrocarbons, from wells where there is insufficient reservoir pressure to produce or finish the well. For water injection, water is injected into a well to provide the reservoir with pressure support, also known as voidage replacement, and to sweep or displace a production product in the well, typically oil, from the reservoir, pushing the production product towards a wellbore exit or producer. For gas lift, the process involves injecting gas, typically through a wellbore or tubing-casing annulus, into a well. Injected gas aerates the fluid in the well to make it less dense. The formation pressure resident in the well is then able to lift the production product and force the production product out of the wellbore. Gas can be injected continuously or intermittently depending on the producing characteristics of the well and the arrangement of the gas-lift equipment.
In sub-sea environments, additional sub-sea support equipment is typically required to lift the production product from the wellbore to the sea surface. In some production environments, the production product is processed or partially processed at or near the sea-floor or mud-line prior to being lifted to the surface. This support equipment can include pumps, centrifuge separators, other multiphase separators, or any equipment that can be disposed at or near the mud-line in the vicinity of one or more wells.
Surface located power distribution systems provide power to the sub-sea support equipment via electrical umbilicals. The umbilicals are supported from the surface by various known devices and routed down to the sub-sea support equipment. The umbilicals must be capable of handling the sub-sea environments and capable of delivering power to the equipment. The sub-sea environmental and service requirements imposed on the umbilicals necessitate the use of umbilicals that are expensive, bulky, and relatively hard to manage.
A need exists to provide power to sub-sea equipment using methods and processes that can reduce the complexity of or completely eliminate the need for surface supported electrical umbilicals.